This article discusses the potential promise and limits of oversight of corporate managers by major institutional investors. I discuss the reasons to believe that, at least for systemic issues that arise at many firms, there can be value is assigning one set of loosely watched agents (institutional money managers) to watch another set (corporate managers). This is partly because, as long as it takes a number of institutions to strongly influence corporate actions, the institutions can also watch each other, thus reducing the risk that any one of them will extract private benefits from the firm. The case for shared institutional voice (with six or ten institutions, often different types of institutions, exercising joint influence) is stronger than the case for direct institutional control of a firm by a particular institution.